Hepatic pathology in Capillaria hepatica infected mice

Abstract

Septal fibrosis of the liver regularly develops in rats infected with Capillaria hepatica. To find out whether such fibrosis also occurs in mice, 20 animals were submitted to infection with either 100 or 300 embryonated eggs and histologically examined after several periods of time, from 30 to 110 days afterwards. Results showed that mice developed acute, severe, diffuse and focal hepatic lesions that were soon modulated to focal areas of fibrosis containing eggs and worm remnants, despite the fact that a few worms remained alive, at least up to 110 days after inoculation. Areas of perisinusoidal fibrosis appeared in the proximity and around focal parasitic lesions, but clear-cut septal fibrosis was not observed. Whey septal fibrosis forms in rats, but not in mice during C. hepatica infection, only further studies can clarify. Mice seem to show better host/parasite relationship than rats in regard to C. hepatica infection.

Experimental hepatic fibrosis due to Capillaria hepatica infection (differential features presented by rats and mice)

“…This type is supposed to be particularly prone to degradation and resorption, as demonstrated by Lortat-Jacob et al (1997) in experimental schistosomiasis under treatment. But, even if one considers the fibrosis that is part of the encapsulating process around dead worms and eggs, it also undergoes advanced degradation with time, to an effect that many eggs appear later on free within the hepatic parenchyma, as registered by Gotardo et al (2000).…”

“…All the pictures above were taken at magnification X200. velop septal fibrosis (Gotardo et al 2000), no further studies are apparently on record. Since C. hepatica-induced fibrosis in mice disappears so rapidly and expontaneously, it may turn to be an adequate model for studies on the factors and mechanisms involved in extra-cellular matrix breakdown.…”

“…These different time points for rats and mice were intended to represent the most characteristic periods of the acute, intermediate, and chronic phases of the infection, according to previous experience of this laboratory (Ferreira & Andrade 1993, Gotardo et al 2000.…”

“…However, the potential of the model is somewhat limited by the peculiarities connected with the experimental host -the rat -because of the difficulties related to the obtaining of commercial kits to study cytokines, chemokines, receptors, growth factors, cells and extra-cellular tissue markers, and so on. Inasmuch as it was also observed that the septal fibrosis, so characteristic of the rat infection, did not occur in the mouse (Gotardo et al 2000). However, the pathology of capillariasis in the mouse also includes the presence of chronic inflammation and fibrosis and other features worth of attention as far as hepatic fibrosis is concerned.…”

Patho-physiological observations in natural concurrent infections of helminth parasites of zoonotic importance in the wild rodents, Bandicota bengalensis

“…On further investigation, these rats were apparently found infected with C. hepatica. The eggs of C. hepatica accumulate in liver in the form of irregular white or yellow patches and streaks on the external surface (Gotardo et al 2000).…”